Buggy code:
public class WeavingAdaptor { public static final String WEAVING_ADAPTOR_VERBOSE = "aj.weaving.verbose" ; public static final String SHOW_WEAVE_INFO_PROPERTY = "org.aspectj.weaver.showWeaveInfo" ; protected boolean enabled = true ; protected boolean verbose = WeavingAdaptor . getVerbose ( ) ; protected BcelWorld bcelWorld = null ; protected BcelWeaver weaver = null ; protected IMessageHandler messageHandler = null ; protected GeneratedClassHandler generatedClassHandler ; protected Map generatedClasses = new HashMap ( ) ; protected WeavingAdaptor ( ) { } public WeavingAdaptor ( WeavingClassLoader loader ) { } public WeavingAdaptor ( GeneratedClassHandler handler , URL [ ] classURLs , URL [ ] aspectURLs ) { } private List getFullClassPath ( ClassLoader loader ) { } private List getFullAspectPath ( ClassLoader loader ) { } private static boolean getVerbose ( ) { } private void init ( List classPath , List aspectPath ) { } private void createMessageHandler ( ) { } public void addURL ( URL url ) { } public byte [ ] weaveClass ( String name , byte [ ] bytes ) throws IOException { } private boolean shouldWeave ( String name , byte [ ] bytes ) { } protected boolean accept ( String name , byte [ ] bytes ) { } protected boolean shouldDump ( String name , boolean before ) { } private boolean shouldWeaveName ( String name ) { } private boolean shouldWeaveAnnotationStyleAspect ( String name , byte [ ] bytes ) { } private byte [ ] getWovenBytes ( String name , byte [ ] bytes ) throws IOException { } private byte [ ] getAtAspectJAspectBytes ( String name , byte [ ] bytes ) throws IOException { } private void registerAspectLibraries ( List aspectPath ) { } private void addAspectLibrary ( String aspectLibraryName ) { } private static List makeClasspath ( String cp ) { } protected boolean info ( String message ) { } protected boolean warn ( String message ) { } protected boolean warn ( String message , Throwable th ) { <START_BUG> return messageHandler . handleMessage ( new org . aspectj . bridge . Message ( "Register<seq2seq4repair_space>definition<seq2seq4repair_space>failed" , IMessage . WARNING , th , null ) ) ; <END_BUG> } protected boolean error ( String message ) { } protected void dump ( String name , byte [ ] b , boolean before ) { } protected class WeavingAdaptorMessageHandler extends MessageWriter { private Set ignoring = new HashSet ( ) ; private Kind failKind ; public WeavingAdaptorMessageHandler ( PrintWriter writer ) { } public boolean handleMessage ( IMessage message ) throws AbortException { } public boolean isIgnoring ( Kind kind ) { } public void ignore ( IMessage . Kind kind ) { } public void dontIgnore ( IMessage . Kind kind ) { } } private class WeavingClassFileProvider implements IClassFileProvider { private UnwovenClassFile unwovenClass ; private List unwovenClasses = new ArrayList ( ) ; private UnwovenClassFile wovenClass ; private boolean isApplyAtAspectJMungersOnly = false ; public WeavingClassFileProvider ( String name , byte [ ] bytes ) { } public void setApplyAtAspectJMungersOnly ( ) { } public boolean isApplyAtAspectJMungersOnly ( ) { } public byte [ ] getBytes ( ) { } public Iterator getClassFileIterator ( ) { } public IWeaveRequestor getRequestor ( ) { } } }

Fix:
return messageHandler . handleMessage ( new org . aspectj . bridge . Message ( message , IMessage . WARNING , th , null ) ) ;